Flashlight switch



Feb. 6, 1951 MaoLEAN FLASHLIGHT SWITCH 2 Sheets-Sheet 1 Filed Feb. 1,1949 Inventor:

'l'homng Traill MacLean w ns w $W.

Attorneys:

Feb. 6, 1951 MacLEAN FLASHLIGHT SWITCH 2 Sheets-Sheet 2 Filed Feb. 1,1949 5 y a n r O t t A Inventor:

Thomas Traill MacLean S Patented Feb. 6, 1951 FLASHLIGHT swrcrcn ThomasTraill MacLean, London, England, as-

signor to Anglo-Iranian Oil Company Limited, London, England, a Britishjoint stock corporation Application February 1, 1949, Serial No. 74,021In Great Britain February 3, 1948 The invention relates to switch meansfor electric torches and has among its objects to provide switch meanssuch that the electric torch may be used with safety in an atmospherecontaining inflammable gases.

Various forms of torch are known which incorporate safety means (such asa mercury switch) to ensure that the torch can only be used in certainpositions. Attempts have also been made to render torches flameproof bythe provision of a seal, such as a rubber diaphragm, through which partof the switch mean passes so as to be accessible from the outside of thetorch casing. Such torches suffer from the disadvantage that the sealingmeans is liable to crack in service, and the fitting of new sealingmeans is not an operation which can be carried out easily and quickly.

The present invention overcomes these disadvantages and provides switchmeans which can be used in any position and can be easily and quicklyassembled or replaced in the torch,

According to the invention, switch means for an electric torch comprisesa mass which may be caused to alternate between two stable positions inwhich the light in respectively on and off, without the use of meanspassed through the torch casing.

According to the preferred embodiment, the

switch means comprises a mass which is caused to alternate between twostable positions by imparting momentum thereto.

According to one such embodiment, the switch means comprises a metallictube secured to contacts at its ends, the tube being in permanentelectrical connection with one of the contacts, while electricalconnection between the tube and the other of the contacts is effected bymean of a ball or slug freely movable within said tube.

According to another such embodiment, the switch means comprises atoggle-actuated weight that is mounted between a pair of electricalcontacts, one of said contacts being in permanent electrical connectionwith said weight, while electrical connection between the other of saidcontact and said weight is only effected when said weight is moved intocontact therewith.

Two embodiments of the switch will now be described by way of examplewith reference to the accompanying drawings, wherein:

' Figure 1' is a vertical section through a torch having switch meansaccordin to the first embodiment,

Figure 2 is a section of the switch means,

3 Claims. (Cl. 200'60) Figure 3 is a fragmentary view of Figure 2 on anenlarged scale,

Figure 4 is an end view in the directionof the arrow in Figure 3, and

Figure 5 is a vertical section through a torch having switch meansaccordin to the second embodiment.

Referring first to Figures 1 to 4, the torch comprises a casing Illclosed at the lower end and within which are contained the twin cells IIof the battery and the switch means I2 provided-according to the presentinvention. A bulb I3 is mounted in the normal way in a reflector I i butcontact of the bulb with the batter is made by way of a spring contactI5 whereby damage to the contact of the bulb due to the impact of theswitch is avoided or reduced.

Referring particularly to Figures 2 to 4, the switch means comprises anelectrically conducting tube I6 secured by means of peripheral flangesI? at its ends to insulatin discs IS which make a sliding fit in thecasing and are of greater diameter than the flanges I I whereby the tubeI 5 is insulated from the casing. An electrically conducting plate I9 ofthe same diameter as the adjacent flange I! is secured to one of theflanges I? by means of metal rivets 20 whereby the plate I9 is inelectrical connection with the flange II. Plates 2I of ferrous metal aresecuredbetween the flanges H and the insulating discs I8. A metalliccontact 22 is secured to a spring contact 23 located within an aperture2Ia in the ferrous plate 2| by means of a metallic rivet 24 whereby thecontact 22 is in electrical connection with contact 23. A magnetised slu25 makes a close but sliding fit within the tube I6 and may be attractedto either of the ferrous plates 2! by means of a jerk imparted to thetorch in the appropriate direction.

It will be seen that when the magnetised slug 25 is in contact with theferrous plate connected to the contact I9, as shown in Figure 2, theswitch is in the oil position since there is no electrical connectionbetween the contact 22 and the tube I 6, while when the magnetised slugis in contact with the contact 23, the switch is in the on positionsince the contacts 22 and 23 are in electrical connection and the slugthus makes electrical connection between the contact 22 and the tube I6.

Referring now to Figure 5, the switch means comprises a U-section metalframe 25 supported between two insulating discs 21. The frame supports aswinging weight 28 with which it is in permanent electrical connection.The frame is also in permanent electrical connection with anelectrically conducting plate 29 mounted on the outside of one of theinsulating discs 27, the diameter of the plate being less than that ofthe disc. The second electrically conducting plate 30, which may be ofsmaller diameter, is mounted on the outside of the second insulatingdisc 21 and is connected with a spring contact 3| secured to the disc 22between the arms of and out of contact with the frame 26. It will beseen that electrical connection between the plates 29 and 30 is securedwhen the swinging weight 28 makes contact with the spring contact 3 i. Ajerk of the torch is sufiicient to make or break such electricalconnection. The Weight 28 is carried by arms 32 that are pivoted attheir ends to the frame 26 at 33, a coil spring 34 being secured at oneend'to the weight 28 and at its other end to a pin 35 which passesthrough slots 36 formed in the arms of the frame 26 and extending oneach side of the pivot 33, whereby the weight 28 is prevented by thespring 32 from taking up a dead position between its two positivecontact positions.

As shown in Figure 5, the switch casing embodies a flame-proof closureas described in the provisional specification of my British applicationNo. 27,431/48, dated October 29, 1948, although it will be understoodthat any other form of flame-proof closure may be used in combinationwith the switch mechanism according to the present invention.

The switch means provided according to the invention is mostconveniently used with a torch having a twin-cell battery, the switchmeans being inserted between the cells of the battery and the casing,but it will be understood that the switch means may be used with thesingle cell type of battery.

A switch means according to the invention is a self-contained unit andneed only be assembled with the battery cell or cells within the torchcasing, no other connections being required. It is thus a simple matterto assemble the torch, and new battery cells or switches may beintroduced easily and quickly.

It will be understood that the invention also comprises an electrictorch having a switch means as hereinbefore described.

I claim:

1. Switch means for an electric torch compris- Number ing a frame, apair of electrical contacts secured one to each end of said frame, oneof said contacts being in permanent electrical connection with saidframe, a weight pivotally mounted on said frame, whereby said weight isadapted by momentum imparted thereto'to make and break electricalconnection between said frame and the other of said contacts, and meansfor maintaining said weight in engagement with one or the other of saidcontacts.

2. Switch means for an electric torch comprising a frame, a pair ofelectrical contacts secured one to each end of said frame, one of saidcontacts being in permanent electrical connection with said frame, aweight pivotally mounted on said frame, whereby said weight is adaptedby momentum imparted thereto to make and break electrical connectionbetween said frame and the other of said contacts, and a spring anchoredat one end to said weight and at the other end to said frame, saidspring holding said weight in engagement with one or the other of saidcontacts.

3. Switch means for an electric torch comprising a frame, a pair ofelectrical contacts secured one to each end of said frame, one of saidcontacts being in permanent electrical connection with said frame, aWeight pivotally mounted on said frame, whereby said weight is adaptedby momentum imparted thereto to make and break electrical connectionbetween said frame and the other of said contacts, and a spring anchoredat one end to said weight and at the other end to a pin slidable in aslot in said frame on the side of the weight pivot remote from theWeight, said spring holding said weight in engagement with one or theother of'said contacts.

THOMAS TRAILL MACLEAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Meginnis May 22, 1934 Lennan Mar. 18,1941 Reavis Apr. 13, 1948

